348 94 348 large valve springs - Ferrari Life
 
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post #1 of 7 Old 04-29-2014, 03:44 PM Thread Starter
 
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94 348 large valve springs

While refreshing the heads on my 94 348 Spider I discovered the outer valve spring tension is low at 27-28 pounds vs. a spec. of 39.6 pounds when compressed 4 mm. I figured this was due to age and fatigue so I ordered another set from Ferrari. The new springs came in between 29 and 34 pounds. So, I sent those back for a replacement set. They are also low (30-34).

Has anyone had this problem and how was it solved ? I've called several Ferrari dealers and they are no help.

Thanks,

Brewman
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post #2 of 7 Old 04-29-2014, 05:10 PM
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Ferrari and valve spring specs, specifically free length, has always been somewhat of fictional tale; you just don't know what to believe. With a proper valve spring compressor, measure the load at 34.00mm. Is it with 5% of specs? Do the same at a compressed length of 25.3mm. See B49 in the WSM.

I suspect that you'll find that your springs are fine...

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post #3 of 7 Old 04-29-2014, 05:37 PM Thread Starter
 
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Originally Posted by David @ FluentInFerrari View Post
Ferrari and valve spring specs, specifically free length, has always been somewhat of fictional tale; you just don't know what to believe. With a proper valve spring compressor, measure the load at 34.00mm. Is it with 5% of specs? Do the same at a compressed length of 25.3mm. See B49 in the WSM.

I suspect that you'll find that your springs are fine...
David, thanks for getting back to me. The load at 34 mm falls between 29 and 34 lbs. on all 64 springs I have on hand. Will take a measurement at 25.3 mm tomorrow and post the results. Compared to the spec. of 39.6 I am well outside the acceptable limit on all springs IF 39.6 is the correct target.

Can you confirm the spec for me and appreciate any other thoughts you might have.

Thanks,

Brewman
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post #4 of 7 Old 05-01-2014, 01:19 PM Thread Starter
 
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Quote:
Originally Posted by David @ FluentInFerrari View Post
Ferrari and valve spring specs, specifically free length, has always been somewhat of fictional tale; you just don't know what to believe. With a proper valve spring compressor, measure the load at 34.00mm. Is it with 5% of specs? Do the same at a compressed length of 25.3mm. See B49 in the WSM.

I suspect that you'll find that your springs are fine...
Quote:
Originally Posted by David @ FluentInFerrari View Post
Ferrari and valve spring specs, specifically free length, has always been somewhat of fictional tale; you just don't know what to believe. With a proper valve spring compressor, measure the load at 34.00mm. Is it with 5% of specs? Do the same at a compressed length of 25.3mm. See B49 in the WSM.

I suspect that you'll find that your springs are fine...
This posting is to extend a HUGE thank you to David at Ferrari Service of Bedford. After calling multiple Ferrari dealers over the last six weeks and getting zero support I put a post on this site. Within one day David answered my questions which allowed me to proceed with refreshing my heads. This is particularly impressive because I am in North Carolina so David had absolutely no opportunity of getting business from me.

In the future I would not hesitate to send my baby to David and recommend him to all members for your future service and parts needs. Not only is David passionate about FCars but he is a genuinely nice person and pleasant to deal with.

Ferrari Service of Bedford

Again, Thanks David.

Brewman
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post #5 of 7 Old 05-01-2014, 02:24 PM
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Quote:
Originally Posted by Brewman View Post
This posting is to extend a HUGE thank you to David at Ferrari Service of Bedford. After calling multiple Ferrari dealers over the last six weeks and getting zero support I put a post on this site. Within one day David answered my questions which allowed me to proceed with refreshing my heads. This is particularly impressive because I am in North Carolina so David had absolutely no opportunity of getting business from me.

In the future I would not hesitate to send my baby to David and recommend him to all members for your future service and parts needs. Not only is David passionate about FCars but he is a genuinely nice person and pleasant to deal with.

Ferrari Service of Bedford

Again, Thanks David.

Brewman

There's none better.
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post #6 of 7 Old 05-02-2014, 03:32 AM
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Thank you for your kind words. Having been down a very similar path about 25 years ago with a 246 Dino, I could fully relate to your concern. Solid technical info can be a real challenge to find. Years back, FNA would actually take calls from independents. Now...well, you've seen first hand the lack of cooperation/knowledge available from the dealer base.

Have fun!

Sarasota Italian Garage, LLC
Sarasota, FL
www.fluentinferrari.com
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Last edited by David @ FluentInFerrari; 05-02-2014 at 12:23 PM.
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post #7 of 7 Old 05-02-2014, 10:27 AM
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Free length specs on any spring are always a bit problematic which is why the standard is normally to spec a spring rate and a seat and nose pressure....then you shim the spring to get the correct pressure making free length of very little importance.

Why Ferrari doesn't just say that I have no idea
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